a) Technical Field
The invention is directed to a method for the production of milled grain products, such as flour, semolina, middlings etc., by means of repeated roll grinding and sifting out specific product fractions in accordance with the system of advanced milling.
b) Background Art
In the production of bread flour, two fundamentally different milling methods are known. Whole-grain or integral/dark flour has been made for a long time by means of grinding the entire kernels once, twice or three times by way of one, two or three grinding passes and possibly sifting out a portion of the hulls or the outermost layer of the kernel.
This system has acknowledged advantages. Virtually all constituents of the kernel remain integral and provide high-value nutrition for persons via bread and other grain products. However, it is equally recognized that this old method, often called flat milling, also has disadvantages. The products yielded by means of integral grinding have only a limited storage life. The corresponding health products are usually intended for immediate consumption. Dirt, bacteria, fungus spores, etc. usually adhere chiefly to the outside of the kernel, on the hull. It is precisely these impurities which destroy the quality of the products and reduce their storage life or increase the risk of spoilage for the milled products and impair the quality of the end products.
The fact that the grain kernel is composed of many very different parts is often ignored. These various parts give the end products of a mill, i.e. the flour, semolina and/or middlings, the required properties, e.g. specific baking characteristics. The possibility of recovering the various parts of the milling kernel in isolation from one another is a precondition for controlling these quality criteria. Such products needed for a specific requirement cannot be separated in an economical fashion in simple flat milling with only a few grinding passes. It is only so-called advanced milling which allows the production of the multitude of starting products presently required for today's modern eating habits.
The modern method is so-called advanced milling which is characterized by a frequently repeated grinding and sifting after every grinding. Until two or three decades ago, this process was often repeated 15 to 20 times. The most recent developments have succeeded in proving that an average of twelve to fifteen grindings already leads to the same results with proper management. Since the early seventies, the short advanced milling method has taken precedence over the previously applied advanced milling method as state of the art throughout almost the entire world.
A good miller is capable of achieving the standard of quality required by industries receiving the product for further processing, e.g. bakers, dough products factories, etc. even from sharply diverging raw materials by means of mixing the different grain qualities and appropriate direction of the milling.
It is well-known that in order to remain in competition the mill must produce a determined quantity of high-quality, and accordingly high-price, end products from a determined quantity of raw materials. That is, a grain mill constantly strives to achieve a high output of light flour, semolina, etc. A mill only operates well when the output is high and the quality criteria are maintained simultaneously. An important aspect of the overall economic efficiency is the extent of required machinery, which, in a mill, depends e.g. directly on the quantity of grinding and sifting units and the necessary space. All recent efforts have shown that the grinding in traditional milling cannot be further reduced without directly reducing the output or the quality of the milled products. To this extent, a stagnation has been observable in the development of the grinding process in milling for some years.